1. Field of the Invention
The present invention relates to a communication device, a communication system and a computer readable medium.
2. Description of Related Art
Conventionally, in an attempt to enjoy a telephone conversation, whether the other party is busy cannot be confirmed without actually calling to ask for his/her convenience. This has been inconvenient when a caller wants to enjoy conversations casually. In addition, in order to confirm the convenience of the other party before calling, the caller has been required to carry out troublesome work such as sending a confirmation e-mail in advance.
For example, the Patent document 1 (Japanese Patent Application Laid Open Publication No. 2003-116165) describes a technique in which presence information indicating a current mood and a condition such as free/busy of a caller is output to the call receiving terminal. In the call receiving terminal, output is carried out by modulating musical tone or such like of the incoming call according to the presence information to inform the other party of the caller's condition.
However, the technique of the Patent document 1 does not consider the condition of the other party though the calling party can tell his/her own condition to the other party. Further, the setting of the caller's current condition (presence information) needs to be updated in each case, and thus the technique is not practical.
In addition, there have been known telephones which have systems for notifying received calls, and telephones which have answering machine functions. However, both types of telephones merely indicate called history. The other party cannot distinguish between a call intended for enjoying a conversation in the caller's free time and a call for urgent business. Therefore, there have been cases where the other party is forced to return the call.